In the telecommunication industry, certain circuits are considered critical, generally because any interruption of the service provided by the circuit would be unacceptable. For instance, circuits used to transport traffic relating to emergency 911 calls and circuits used by the Federal Aviation Administration's air traffic control system often are designated as critical because their failure could lead to catastrophic consequences. Other circuits, including some circuits in a typical Signaling System 7 (“SS7”) network, can be considered critical because a service interruption of such a circuit would negatively impact the provision of telecommunication services to a particular geographical area. On the other hand, many circuits are not considered critical, in that the failure of a single such circuit would have only minimal impact on the provision of telecommunication services.
Circuit failures can result from many sources, including cable cuts, equipment failure, or even power loss or natural disaster at a critical location. In order to guard against the catastrophic failure of a critical circuit, telecommunications providers often build redundancy into their telecommunication networks. For instance, FIG. 1A illustrates a portion of a simple telecommunication network 100. In example network 100, service switching point (“SSP”) 104 is located in Grand Junction, Colo. In order to have telecommunication access to the rest of the world, Grand Junction's SSP is connected by SS7 “A Link” 108 to Signal Transfer Point (“STP”) 112 in Denver, which provides a connection between SSP 104 and the rest of the telecommunication network. In this example, A Link 108 is a critical circuit because, if it suffered a service interruption, Grand Junction would have no connectivity to STP 112. To remedy this problem, a telecommunication provider typically would provide an additional A Link 116 between SSP 104 and a second STP 120. In this way, if A Link 108 were cut, connectivity would be maintained by A Link 116.
This redundancy fails, however, if both A Links 108, 116 use the same telecommunication facilities or equipment. For instance, if A Links 108, 116 occupy channels on the same T1 line for at least part of the distance from Grand Junction to Denver, a single cut to that T1 line would sever both A Links 108, 116, such that connectivity between Grand Junction and Denver would be lost. Thus, in order to obtain the full benefits of redundancy, the critical circuits must exhibit complete diversity of facilities, cable and equipment.
In reality, however, diversity violations are commonplace in telecommunication networks because of the nature of such networks. Most telecommunication providers use a provisioning system, for example the Trunks Integrated Records Keeping System (“TIRKS®”) from Telcordia Technologies, Inc., to provision and track circuits in their telecommunication networks. Unfortunately, such systems often provision circuits according to the most efficient path between two switches, such that multiple circuits between two switches usually will be carried on the same facilities, and often on the same equipment, without regard to diversity considerations. Moreover, even if two circuits are diverse as originally provisioned, those skilled in the art can appreciate that normal network churn often will result in the automatic re-provisioning of those circuits, which often destroys any diversity originally built into the circuit design. Compounding the problem, provisioning systems generally offer no means of determining whether two circuits are diverse (or even of tracking whether they should be diverse).
What is needed, therefore, is a tool for analyzing the diversity of critical circuits. Ideally, such a tool should allow a user to identify two or more critical circuits that require diversity, analyze the facilities and equipment utilized by each identified circuit, and display for the user a list of any common facilities or equipment, so that the user can determine the location and nature of any diversity violation.